PB2140: ALLOGENEIC STEM CELL TRANSPLANTATION IN RARE T-NHL SUBTYPES: FOCUS ON AITL, MF/SS, HSTCL. A SINGLE BMT-UNIT EXPERIENCE.
Authors: T. Tzenou, A. Roumelioti, N. El Gkotmi, P. Christoforou, N.-E. Loutsidi, A. Apsemidou, I. Tzannou, T. Ioannis, C. Giatra, F. Karaolidou, Z. Mellios, B. Maria, S. Gigantes, I. Baltadakis, D. Karakasis
Journal: HemaSphere (2022)

Background: Angioimmunobastic Lymphoma (AITL) and T-γδ-hepatosplenic lymphomab(HSTCL) consist two rare, aggressive T-NHL subtypes while patients with Mycosis Fungoides/Sézary (MF/SS) syndrome may have a more indolent disease course but are rarely cured with conventional therapy. AutoHSCT may offer prolonged survival in selected cases of AITL but relapses are common. Despite the significant innovation in therapeutics of hematological malignancies, little progress is made in these lymphomas management. Due to the rarety as well as to the fact that at least for AITL and MF/SS median age at diagnosis is greater than 60 years old, there is limited number of reports on allogeneic stem cell transplant outcomes and data from prospective studies are missing Aims: To describe our experience on allogeneic transplant outcomes in a small cohort of relatively young patients with AITL (3), HSTCL (3), MF/SS (8) Methods: Records of 14 patients (6 men, 8 women), who underwent consecutively allogeneic stem cell transplant from 01/01/2008 to 31/12/2019, were retrospectively studied. Survival status was censored on 15th February 2022. All had consented to the use of their data before conditioning initiation Results: Median age was 51.5, 34 and 49 years old in MF/SS, HSTCL and AITL respectively. All donor types had been used. All MF/SS had been submitted to RIC alloHSCT with FLU MEL +/-ATG and no MF/SS patient was on CR at the time of alloHCT (3 PR, 2SD, 3PD). 1 patient with AITL was in CR at the time of alloHSCT and remains alive, relapse and GVHD free 28 months after alloHSCT while 1 patient in PR at the time of alloHSCT is alive in CR, relapse/GVHD free 6 years later. 1 patient with HSTCL is alive relapse/GVHD free 12 years after HSCT. There were no early deaths before day 30 in the whole cohort, while 3 patients died before day 100 – 1 with AITL due to primary graft failure, 2 with MF/SS due to refractory disease. 2 patients with HSTCL died due to early disease relapse, 4 and 6 months post-transplant respectively, while 2 patient with MF/SS died 7 and 15 months post-transplant due to EBV positive PTLD and severe gastrointestinal PTLD complicated by CMV-colitis. At the date of data censoring 4 patients with MF/SS were alive in CR and relapse/GVHD free, while 1 patient was alive but in PR after the second relapse treated with pembrolizumab 39 months after alloHSCT Summary/Conclusion: Due to the rarity of the studied lymphoma subtypes our cohort was small and proper statistical analysis of data could not be done safely. However, it becomes clear that younger patients with MF/SS -even with relapsed/refractory disease - may benefit of prolonged survival with allogeneic stem cell transplant. For patients with HSCTL, allogeneic stem cell transplant is considered “sine qua non” for survival and cure, while fit patients with AITL should be considered candidates for alloHSCT. Immunological manipulation may contribute to relapse management.